1. Field of the Invention
The present invention relates to an internal combustion engine automatic stop/restart device and an internal combustion engine automatic stop/restart method for stopping an internal combustion engine when an automatic stop requirement is satisfied, and restarting the internal combustion engine when a restart requirement is satisfied.
2. Description of the Related Art
In recent years, an internal combustion engine automatic stop/restart device (namely, a device for carrying out so-called idling stop) in combination with an internal combustion engine is generally installed on a vehicle mainly in order to reduce a fuel consumption. Such an internal combustion engine automatic stop/restart device stops the internal combustion engine when a predetermined automatic stop requirement based on a deceleration or stop operation by a driver is satisfied, and restarts the internal combustion engine when a restart requirement based on a start or acceleration operation by the driver is satisfied.
Moreover, as an example of an operation of the internal combustion engine automatic stop/restart device, in order to prevent an excessive load from being applied to, for example, a starter or a power transmission system, when a rotation state of the automatically stopping internal combustion engine is a reverse rotation state, a drive inhibition state of the starter is set to inhibit the restart of the internal combustion engine, which is automatically stopping. Then, after an RPM peak of the internal combustion engine having the rotation state in the reverse rotation state is directly detected (after the RPM of the internal combustion engine takes the minimum value), when the RPM becomes equal to or more than a predetermined RPM, the drive inhibition state of the starter is released.
However, the conventional technology has the following problems.
According to the conventional technology, in order to detect the RPM peak of the internal combustion engine, it is necessary to detect a reverse rotation crank signal (reverse rotation crank angle) of the internal combustion engine at least three times. Therefore, if a period when the rotation state of the internal combustion engine is the reverse rotation state is short, and the reverse rotation crank signal can thus be detected, for example, only twice, the RPM peak cannot be detected.
In this case, there has been such a problem that the drive inhibition state of the starter cannot be appropriately released depending on the rotation state of the internal combustion engine. Moreover, as a result, the drive inhibition state of the starter cannot be released until the rotation of the internal combustion engine stops completely (for example, a period of approximately 200 milliseconds), and there has been such a problem that the period of the drive inhibition state can unnecessarily long.